Does Navigation Improve Accuracy of Placement of Pedicle Screws in Single-level Lumbar Degenerative Spondylolisthesis?: A Comparison Between Free-hand and Three-dimensional O-Arm Navigation Techniques.

STUDY DESIGN: This was a prospective, nonrandomized study. OBJECTIVES: To assess the accuracy of O-arm navigation-based pedicle screw insertion in lumbar degenerative spondylolisthesis and to compare it with free-hand pedicle screw insertion technique in matched population. SUMMARY OF BACKGROUND DATA: O-arm navigation is latest in navigation technology that can provide real-time intraoperative images in 3 dimensions while placing the pedicle screws to improve intraoperative pedicle screw accuracy. Degenerative lumbar spondylolisthesis is a locally unstable pathology and placement of pedicle screws can cause increased rotation and translation of the vertebral body. However, is this motion detected by the tracker placed across the unstable segment, is a matter of debate. Inability to detect these positional changes can lead to pedicle perforation while inserting screws using navigation. No study has evaluated the role of O-arm navigation in this patient population. MATERIALS AND METHODS: The study population was divided into 2 groups with 19 patients each, one comprising patients who underwent O-arm navigation-based pedicle screw insertion (group 1) and the other comprising patients who underwent free-hand pedicle screw insertion technique (group 2). A total of 152 pedicle screws were implanted in 38 patients for 1-level instrumented fusion for degenerative lumbar spondylolisthesis. Intraoperative 3-dimensional computed tomography scans using the O-arm were obtained for all patients after insertion of pedicle screws. The images were reviewed intraoperatively and postoperatively for the analysis of pedicle breaches. Assessments in either of the group included (i) accuracy of placement of screws; (ii) the rate and direction of perforation; and (iii) the number of segments the perforated screw was away from the navigation tracker. RESULTS: Mean age of patients in group 1 (O-arm navigation-assisted) was 60 years (SD 11.25; range, 37-73 y), whereas in group 2 (free-hand pedicle screw) was 62 years (SD 18.07; range, 36-90 y). Overall anatomic perforation rate was 12.5% (19/152). Individually, group 1 had 14.47% (11/76) of perforations in comparison with 10.53% (8/76) observed in group 2. The difference was not statistically significant. The lateral margin was the most common site of perforation in both group 1 (64%, 7/11) and group 2 (62.5%, 5/8). Functional perforation rate for the series was 3.3% (5/152), with group 1 having 2.63% (2/76) and group 2 having 3.95% (3/76). The rate of perforation (PR) was significantly higher statistically when the tracker was placed 3 or more [PR 37.5% (6/16)] spinal segments away from instrumented segment compared with when it was placed 1 (0%) or 2 [PR 13.89% (5/36)] spinal segments away. Overall, 11 screws (11/152, 7.24%) had grade 2 perforations and had to be revised. No neurological complications were observed in the series. CONCLUSIONS: O-arm navigation does not provide any significant advantage over conventional free-hand pedicle screw insertion technique in patients with single-level degenerative spondylolisthesis. The accuracy is dependent on the distance of the tracker from the level of instrumentation. Lateral perforations are more common because of instability at the instrumented level leading to translation and rotation of the vertebral body while placing pedicle screws leading to preferential lateral trajectory. These lateral perforations could not be prevented by using navigation. However, no significant complications were noted in either technique.

Erectile dysfunction in young surgically treated patients with lumbar spine disease: a prospective follow-up study.

STUDY DESIGN: This is a prospective study. OBJECTIVE: The prevalence of erectile dysfunction (ED) in patients younger than 50 years with fracture-unrelated lumbar spine disease requiring surgical decompression without other risk factors for ED is evaluated. SUMMARY OF BACKGROUND DATA: There is little literature documenting ED in young patients with atraumatic lumbar spine disease. METHODS: All male patients younger than 50 years who underwent lumbar spine surgery during June 2006 to November 2007 without risk factors for ED were included. Patient demographics, neurological dysfunction, visual analogue scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), North American Spine Society score for neurogenic symptoms (NS), and the International Index of Erectile function (IIEF-5) scores were recorded preoperatively, at 1, 3, and 6 months. RESULTS: There were 61 patients with mean age 38.4 years (SD = 7.0; range, 20-49). Most of patients had (43 or 70.5%) prolapsed intervertebral disc with discectomy being the commonest operation. Mean VAS scores, ODI, and NS improved significantly postoperatively. However, the mean IIEF-5 scores did not. Preoperatively, there was no correlation between ED and VAS scores on back pain (P = 0.70), leg pain (P = 0.91), ODI (P = 0.93), or NS (P = 0.51). At 6 months, patients with NS > 70 had an increased risk of ED (P = 0.03). Eighty percent of patients with NS > 70 had ED compared with 30% of patients with NS ≤ 70. There was, however, no correlation between ED with ODI (P = 0.38) and VAS scores on back pain (P = 0.20) or leg pain (P = 0.08) at 6 months. CONCLUSION: The incidence of ED in patients younger than 50 years with nonfracture-related lumbar spine disease undergoing surgery without risk factors was 34.3%. Despite improvement in VAS, ODI, and NS scores postoperatively, ED did not improve. Patients with NS > 70 postoperatively were more likely to have ED reflecting possible permanent nerve damage from lumbar spine pathology.

Spontaneous spinal epidural haematomas and the prognostic implications of interval to surgical decompression: a report of two cases.

Spontaneous spinal epidural haematomas (SSEHs) are rare causes of spinal cord compression. We present 2 cases of thoracic SSEHs with similar magnetic resonance imaging (MRI) features. Patient 1 was on long-term oral anticoagulants and patient 2 had uncontrolled hypertension. Patient 1 presented with a dense motor deficit, whereas patient 2 developed progressive lower limb weakness. Decompression laminectomy and haematoma evacuation was performed 51 hours later for patient 1 and 14 hours later for patient 2. Both had recovered their lower limb power, but neurological recovery was greater for patient 2. In patients with bleeding diatheses or uncontrolled hypertension, acute SSEHs must be suspected when they present with atraumatic back pain and signs of spinal cord compression. The interval to surgical decompression greatly influences the prognosis for neurological recovery.